Thousands of people were either watching or taking part in the parade and the blast took place on a street parallel to where participants dressed in colourful folkloric costumes were making their entrance to the Carnival in the city of Oruro.

Two children were among the dead and a total of 28 were injured.

Police deputy commander Freddy Betancurt said investigators believe the explosion was caused by hot oil weakening the hose to the vendor's gas canister.